To provide a web pressure device in a paper manufacturing machine, suitable for use in dehydrating web under pressure and designed to easily and surely attach/detach a blanket to/from a support without folding the end of the blanket.

This web pressure device works as follows: a web 45 is allowed to travel between a cylindrical blanket 135 mounted on a support 31 and a press roll 43 and pressurized by the aid of both the blanket 135 and the press roll 43. This pressurizer includes a blanket fixing means 1 functioning to fix the blanket 135 onto a flange rotary member 134 equipped rotatably on the end of the support 31 in a condition of holding the end of the blanket 135 nearly circularly; wherein the means 1 presses the blanket 135 by the aid of a guide ring 156 in contact with the outer circumferential face of the end of the blanket 135 and a pressure ring in contact with the inner circumferential face of the end of the blanket 135.